1. Field of the Invention
The present invention generally relates to linearization apparatuses for measured value-producing impedance means, and more particularly to a linearization apparatus for a first measured value-producing impedance means which is series-connected with a second impedance means over a voltage source, the apparatus having feedback means to compensate for a change in potential relative to a reference potential, which change in potential has been caused by the first impedance means at the junction thereof with the second impedance means.
2. Description of the Prior-Art
Various types of impedance transducers are available, and by way of example mention should here be made of the temperature-sensitive resistance transducer in connection with which the invention will be described hereinbelow.
Like most transducers, the temperature-sensitive resistance transducer, for example a resistor whose resistance is dependent upon temperature, has a characteristic which is non-linear, that is, changes in the temperature of the transducer do not give rise to changes in the resistance of the transducer, which are proportional to said temperature changes.
Transducers of this kind are often employed in some type of bridge connection, it being extremely desirable to obtain an output signal which is linearly related to the quantity, that is the temperature, to which the transducer is responsive.
It can be shown in a simple way that not even a transducer having a linear characteristic provides in conventional bridge connections an output signal which is linearly dependent upon the variable of measured values. The non-linearity inherent in the bridge connection is normally amplified by the non-linearity of the transducer characteristic.
The method most common at present of linearizing a dependent signal which varies non-linearly with an independent variable, aims at effecting, within predetermined intervals of the range of values of the signal, an approximation by means of suitable straight lines. This method is expensive and nevertheless gives rise to errors of approximation which increase with the size of the approximation intervals and the degree of curvature of the characteristic.